170 THE WONDER OF LIFE 



also be borne in mind that certain of our summer visitors 

 in Britain keep on arriving for a long time different 

 contingents probably coming from different winter-quar- 

 ters. Thus in the sixth Report of the Migration Com- 

 mittee of the British Ornithological Club it is recorded that 

 ' the immigration of the wheatear (including both races) 

 extended over a longer period than that taken by any 

 other species, the first arrivals (in 1910) being observed 

 on March 6, the last on May 19. Other species occupying 

 a prolonged period were the willow- warbler (March 19 

 to May 19) and the whin-chat (March 26 to May 23), 

 while the shortest time seems to have been taken by the 

 wood- warbler (April 11 to May 6). The average length of 

 the arrival period for 1910 was about five or six weeks '. 

 For the same year the first bird to return was the chiff-chaff 

 on March 5, but except for a few species the immigration 

 did not really set in till April 2. Most of it was over by 

 the end of the third week in May. The largest movement 

 occurred on May 2, when no fewer than twenty-five 

 different species arrived simultaneously on the British 

 coasts. 



On the whole, however, the regularity of the migratory 

 movement is impressive, and Professor Alfred Newton 

 wrote thus about it long ago 



' Foul weather or fair, heat or cold, the puffins repair to 

 some of their stations as regularly on a given day as if 

 their movements were timed by clock-work. Whether they 

 have come from far or from near we know not, but other 

 birds certainly come from a great distance, and yet they 

 make their appearance with scarcely less exactness. Nor 

 is the regularity with which certain species disappear much 

 inferior ; every observer knows how abundant the swift 



